Micro morphological foliar taxonomic studies of genus Paspalum based on scanning electron microscopy.

Paspalum is one of the 10 largest genera in Poaceae and is considered as a complex and taxonomically difficult genus due to its similar morphological characters within the species which makes it difficult to delimit taxa within the same genus. The current research work establishes the distinction among species of this genus and resolves taxonomic confusions among this genus. And this distinction is done by micro morphological foliar anatomical characterization by light and scanning electron microscopy. Both the abaxial and adaxial epidermal cuticles of three different species of genus Paspalum were studied and their phytoliths were observed through elemental dispersive spectrophotometric analysis by SEM first time in Pakistan. Results showed great variation in studied anatomical features. P. dilatatum Poir. was comprised of macro-hairs in the intercostal regions only whereas no macro-hairs were found in P. distichum Linn. and P. scrobiculatum Linn. Beak-shaped prickles were found in the intercostal regions on adaxial surface only in P. distichum Linn. and P. scrobiculatum Linn. whereas in P. dilatatum Poir., knife-shaped prickles were present in intercostal regions only on both abaxial and adaxial surfaces of leaf epidermis. No papillae were seen in P. dilatatum Poir whereas in P. distichum Linn. and P. scrobiculatum Linn. papillae were found abundantly. In genus paspalum, P. dilatatum Poir. phytoliths showed lowest mass percentage of silicon as 15.13% whereas P. distichum Linn. phytoliths showed highest mass percentage of silicon as 22.00%. Based on micro morphological foliar characteristics a taxonomic key of studied species is also provided to delimit the taxa.